For example, a wristwatch which has an analogue display function for moving a hand above a dial, and a digital function for electrooptically displaying information such as time by a display element such as a liquid crystal display element has been well known. Both of the analogue and the digital functions are illuminated by one illumination device.
The wristwatch of this type is provided with a light guide plate on a lower side of a transparent or translucent dial, which receives light of a light-emitting diode from a side surface to guide the light in a surface direction of the light guide plate. The liquid crystal display element is disposed in the lower side of a notch-for-display corresponding to a display window portion of the dial. When making the light emitting diode emit light in this state, the light is received in the light guide plate and is guided in the surface direction. This guided light is radiated from the upper surface of the light guide plate and the end surface of the notch-for-display of the light guide plate, thereby illuminating the upper side thereof through the dial and also, illuminating the liquid crystal display element from periphery thereof.